先两边同时开三次方,x²+y²-1=yx^2/3y²-yx^2/3=1-x²(y-0.5x^2/3)^2-0.25x^4/3=1-x²y-0.5x^2/3=正负根号下（1-x²+0.25x^4/3）y=正负根号下（1-x²+0.25x^4/3）+0.5x^2/3...